1. Field of the Invention
The present invention relates to the use of compounds of the optical brightener family in a cosmetic composition or for the preparation of a dermatological composition, for topical application. The composition imparts greater uniformity, greater homogeneity greater clarity, an alabaster-smooth appearance and greater whiteness to the complexion of the skin. Such compositions may also have shadow-concealing properties.
The invention also relates to the compositions which contain compounds of the optical brightener family in combination with other cosmetically useful compounds, such as skin bleaching agents, screening agents, anti-wrinkle agents and moisturizers.
Additionally, the present invention relates to a process for the immediate bleaching of the skin, by applying to the skin a cosmetic composition comprising at least one compound of the optical brightener family.
2. Description of the Background
It is common for people with colored or even dark skin to wish to lighten the skin, and, with this aim, to use cosmetic or dermatological compositions containing bleaching agents.
The substances most commonly used as bleaching agents are hydroquinone and its derivatives, kojic acid and derivatives thereof, azelaic acid, arbutin and derivatives thereof, alone or in combination with other active agents.
Such compositions comprising bleaching agents are also used by individuals whose skin displays dyschromias. These dyschromias are of diverse origin: age (age marks), exposure to UV radiation, pregnancy mask, skin pathology, etc.
However, these agents are not without drawbacks. In particular, it is necessary to use them for a long period and in large amounts in order to see a bleaching effect on the skin. No immediate effect is observed when compositions containing them are applied.
In addition, hydroquinone and its derivatives are used in an amount which is effective to observe a bleaching effect. In particular, hydroquinone is known for its cytotoxicity towards melanocytes.
Moreover, kojic acid and its derivatives have the drawback of being expensive and, for this reason, of not being able to be used in large amounts in products for mass marketing.
It is known practice to use cosmetic compositions which are capable of making the complexion uniform and optionally of giving an immediate white appearance, these compositions consisting of powders dispersed in a binder. The powders generally contain white or colored pigments depending on the desired effect, and fillers in lamellar form, or alternatively silica in the form of platelets. The uniforming effect on the complexion is obtained essentially by virtue of the covering power provided by the fillers in lamellar form.
The drawback of such compositions is that the smoothing out of the skin's defects is provided by the covering power of the compositions. Skin bearing make-up in this way loses its natural appearance on account of the lack of clarity of these compositions.
Although it has been possible to consider using lamellar fillers as a means for increasing the clarity of these compositions (see for example U.S. Pat. No. 4,899,163), they have the drawback of acting by reflecting light and give the skin an unnatural shiny appearance.
There is, therefore, still a need for cosmetic and/or dermatological compositions for obtaining a homogeneous, uniform, white complexion of natural appearance, where these compositions having satisfactory clarity after they have been applied to the skin.
French patent application FR-2,741,261 describes cosmetic compositions comprising a brightening fluorescent agent, these agents also known as optical brighteners. These agents have the advantage of intensifying the radiance and brightening the colors of cosmetic compositions comprising them when they are applied to the skin or the hair. The effect of these agents is observed on a colored support (the hair) or in a colored composition (make-up such as mascara, nail varnish or lipstick). However, the effect of optical brighteners on the skin itself as described above is neither disclosed nor suggested therein.